1. Field of the Invention
The present invention generally relates to a light emitting diode (LED) street lamp, and more specifically to an LED street lamp having a nano-enamel layer and a thermally radiative heat dissipation film.
2. The Prior Arts
With the advanced progress in the technology of LED and the well developed peripheral control circuits, LED has become one of the most important light sources. In particular, LED does not contain mercury so as to meet the requirement of Rohs (Restriction of Hazardous Substances Directive) related to the Restriction of the use of certain hazardous substances in electrical and electronic equipment by European Union. Moreover, LED has been widely used in the mobile phone, the backlight module of LCD monitor and television, the projector and general lighting device because of high lumen, low power consumption, long lifetime and high color rendering index.
As for the application of LED, there are many shortcomings about the traditional LED lamp including a plurality of LEDs with low yield, weak connection, chromatic aberration and high maintenance cost. As the technology in the light guiding developed, the illumination device using the high light emitting LEDs has become more popular. However, the power of the high light emitting LED increases as the intensity desired increases, the working temperature of the LED may thus considerably increase. The efficiency of heat dissipation for traditional LED packages is usually low so as to cause lower light emitting and shorter lifetime of the LED lamp or other LED products due to thermal effect. Therefore, how to solve low heat dissipation is a key issue in the LED applications.
In the prior arts, an LED street lamp generally includes a lamp post, an aluminum extrusion casing, a substrate, LED bulbs and a lamp shade. The aluminum extrusion casing is manufactured from aluminum blocks or aluminum alloy blocks by the aluminum extruding process. The substrate is provided in the aluminum extrusion casing to receive the external power and signals. The LED bulbs are provided on the substrate. The lamp shade and the aluminum extrusion casing are jointed together to enclose the substrate and the LED bulbs. The lamp shade is usually made from glass or acrylic plastic to provide light transparency.
However, the surface of the aluminum extrusion casing is easily oxidized and a blocking film tends to form due to water or dust adhering to the surface such that the propagation of the heat is greatly influenced and the heat dissipation is deteriorated. Also, the light emitting and the lifetime are reduced. Additionally, the traditional street lamp is much heavier and expensive because the aluminum extrusion casing removes the heat generated by the LED bulbs by thermal conduction and it needs more aluminum alloy to form the aluminum extrusion casing with larger thickness such as 30 cm to enhance thermal conduction.
Therefore, it is desired to provide a new LED street lamp without the aluminum extrusion casing to overcome the above problems in the prior arts.